Thank you, I did just that! :D
4. Checking for membership in an environment sounds like a (very) decidable
problem. It maybe simpler to just write a judgment form for the positive
case, and simply defining the negative case as “when the judgment doesn’t
hold”.
A sexta-feira, 9 de abril de 2021 à(s) 01:20:32 UTC+1, philngu...@gmail.com
escreveu:
> It’s difficult without seeing the definitions, but here are a few general
> comments:
>
> 1. Cases in judgment forms are not run in order. If multiple cases match,
> they’ll all hold. For example, in this case, if (anotin ((a -> b ...)) a
> #t) holds, (anotin ((a_0 -> b ...)) a #f) will also hold.
>
> 2. If your environment looks something like ((a_1 -> b_1) (a_2 -> b_2)
> (a_3 -> b_3)), the pattern for the second case should be (_ ... (a -> b)
> _ ...). The ellipses after b as it currently is means a sequence of zero
> or more b’s.
>
> 3. The relation is being named “not in”, but it seems like it’s computing
> both “in” and “not in” cases, which is confusing.
>
> 4. Checking for membership in an environment sounds like a (very)
> decidable problem. It maybe simpler to just write a judgment form for the
> positive case, and simply defining the negative case as “when the judgment
> doesn’t hold”.
>
> On Wednesday, April 7, 2021 at 9:57:15 AM UTC-7 beatriz@gmail.com
> wrote:
>
>> Hello,
>> I'm trying to write a side condition to a function, where it checks if a
>> is in an environment ß. I tried this judgement by adding (judgment-holds
>> (anotin (ß-v ...) a #f)) at the end of the function but it is not
>> working :(
>> Thank you!
>> --Beatriz
>>
>> (define-judgment-form Flint
>> #:mode (anotin I I O)
>> #:contract (anotin env-ß a boolean)
>> [-
>>(anotin () a #f)]
>> [-
>>(anotin ((a -> b ...)) a #t)]
>> [-
>>(anotin ((a_0 -> b ...)) a #f)]
>> [-
>>(anotin (ß-v_0 ... (a -> b ...)) a #t)]
>> [(anotin (ß-v ...) a boolean)
>>-
>>(anotin (ß-v ... (a_0 -> b ...) ) a boolean)]
>> )
>>
>
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